If you choose DDUtility the first page allows you to chose flex or legacy radios. That allows Ddutil to select the proper cat commands. And of course you attach this program to the correct. Cat port. Electronic port.

Doing this correctly will display frequency info.

The next pages on the setup give you access to different amps. Watt meters. Etc.

If it is not listed. You will need to create a virtual com port pair and allow the radio to talk with one port and broadcast to the amplifier port again DDUtility allows you to do this. Also commander will also allow this. (Easier in my opinion)
There is a detailed how to hook up a om amplifier. Using Ddutil. Here in the community pages. Follow that solution. Just do it with the a com.